JP2018071823A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater capable of securing a warming function on the basis of a warming operation while preventing the warming operation from continuing over an excessively long time in a warming operation control during standby for water heating.SOLUTION: When the temperature in a detection passage decreases to a warming operation starting temperature or lower, a warming operation is started and integration of burning time is started (YES in S3, S4, and S5). When the integrated burning time is the set burning time or less (YES in S6), and the temperature in the passage increases to the warming operation stopping temperature or higher (YES in S7), the warming operation is stopped (S8). When the temperature does not increase to the warming operation stopping temperature, and the integrated burning time exceeds the set burning time (NO in S6), restrictions on the upper limit of a burning stage is relaxed and the number of stages is increased (S10). If, in spite of the relaxation of the upper limit, the temperature does not increase to the warming operation stopping temperature within the set burning time, processing of +α increase to a burning amount arithmetic result is executed, in addition to second upper limit relaxation processing (S10).SELECTED DRAWING: Figure 3

Description

  According to the present invention, hot water at a predetermined temperature can be immediately brought into use at the time of the next use of hot water by circulating and heating the hot water in the hot water supply path back to the water supply side during hot water supply standby (when hot water is not used). The present invention relates to a hot water supply device having a heat retaining function, and particularly relates to a technique capable of avoiding a combustion operation for a heat retaining operation being continued for an excessively long time.

  Conventionally, a hot water supply device having a heat retaining function for instant hot water is known. For example, Patent Document 1 includes a return path branched from a hot water supply path in front of the hot water tap and joined to the water supply path, and a circulation pump for returning and circulating hot water through the return path. It is described that the heat retention operation control is performed in which the circulating pump is operated to heat the circulating hot water by combustion.

  Further, in Patent Document 2 (see, for example, paragraph 0035), hot water staying in the heat exchanger is targeted and the combustion burner is operated without being circulated at the time of hot water supply standby. In the case of performing heat insulation combustion control in which the staying hot water is heated, it is described that the heat insulation combustion is automatically stopped when a set time elapses from the time when the combustion for the heat insulation is started.

Japanese Patent No. 5708975 Japanese Patent No. 3098730

  By the way, the pipes installed for hot water supply from the hot water supply device to the hot water tap and the pipes installed for the return path for the heat insulation operation are installed outdoors depending on the installation site, or are installed over a relatively long distance. May be. For this reason, it becomes easy to be influenced by the outside air temperature based on seasonal fluctuations, and there is a possibility that inconvenience may occur due to an increase in heat radiation while passing through the pipe (hereinafter referred to as “pipe heat radiation”). For example, during hot water standby, hot water is returned from the hot water supply path to the water supply path through the return path by the operation of the circulation pump, heated by the combustion burner, and then circulated to the hot water supply path. When the temperature drops to a predetermined heat insulation operation start temperature, the circulation pump and the combustion burner are operated to start the heat insulation operation. When the temperature of the circulating hot water rises to the predetermined heat insulation operation stop temperature, the circulation pump and the combustion burner are operated. Considering the case where the heat insulation operation control of stopping the heat insulation operation and stopping the heat insulation operation is considered, the following inconvenience may occur.

  That is, even if the hot water returned from the hot water supply passage is heated by the combustion burner, when the amount of heat released by the heat radiation from the pipe is relatively large, the temperature rise of the circulating hot water becomes dull, and as a result, the combustion of the combustion burner continues for a long time. Even if it is made to happen, the case where it does not rise to the heat insulation operation stop temperature may occur. In this case, the heat retention operation does not stop, and the combustion operation continues until the next hot water supply is used.

  This invention is made | formed in view of such a situation, The place made into the objective is that the heat insulation operation will continue over an excessively long time in the heat insulation operation control performed at the time of hot water supply standby. An object of the present invention is to provide a hot water supply apparatus that can ensure a heat retaining function based on a heat retaining operation while avoiding the heat retaining operation.

  In the present invention, a water supply channel, a heating unit for heat exchange heating of water supplied through the water supply channel by combustion heat, and hot water heat-exchanged and heated by the heating unit toward the hot water supply destination A hot water supply path, a circulation path including a return path for branching from the vicinity of the hot water supply destination to return hot water to the water supply path, a circulation pump, and operating the circulation pump during hot water supply standby to Targeting a hot water supply apparatus provided with a heat insulation operation control part for performing a heat insulation operation for keeping the inside of the circulation path by circulating hot water heated by a heating part between the hot water supply destinations, We decided to prepare matters. That is, a temperature sensor for detecting the temperature in the hot water in the circulation path is provided. Then, as the heat retention operation control unit, the circulating hot water is heated by operating the heating unit in a range of an initial set upper limit combustion amount that is limited to be lower than the upper limit combustion amount during the hot water supply operation, and the temperature When the temperature in the detection path detected by the sensor is equal to or lower than a preset warming operation start temperature, the warming operation is started, while the temperature in the detection path is equal to or higher than a preset warming operation stop temperature by the warming operation. If the temperature rises, the heat insulation operation is stopped. In addition, as the heat insulation operation control unit, if the temperature in the detection path does not rise above the heat insulation operation stop temperature even after a predetermined set time has elapsed since the heat insulation operation was started, the upper limit of the initial setting The restriction content related to the upper limit combustion amount is updated by performing an upper limit relaxation process for increasing the combustion amount within a range equal to or lower than the upper limit combustion amount during the hot water supply operation (Claim 1).

  In the case of this invention, for example, at the turn of the season when the outside air temperature drops rapidly, the heat radiation of the pipe increases, and as a result, most of the heat applied by the combustion in the heating unit is lost by the heat radiation of the pipe. Even if the circulation based on the heat insulation operation is continued, even in an environment where the temperature of the circulating hot water has hardly increased, the heating unit continues to burn for an excessively long time as the heat insulation operation is performed. It becomes possible to avoid the situation. That is, if the detection path temperature does not rise to the heat insulation operation stop temperature even after the set time has elapsed, an upper limit relaxation process is performed to increase the initial upper limit combustion amount within the range of the upper limit combustion amount during the hot water supply operation. Therefore, if the amount of combustion determined according to the temperature of hot water returned by the circulation path including the return path exceeds the range of the upper limit combustion amount of the initial setting, the amount of combustion can be increased. Thus, the temperature rise up to the heat insulation operation stop temperature can be obtained early. On the other hand, after the heat insulation operation is stopped due to the temperature rise, it is considered that the temperature in the road is quickly lowered to the heat insulation operation start temperature, so that the next heat insulation operation is started early, so that the heat insulation function in the environment is also provided. It will be possible to secure it properly.

  Further, in the hot water supply apparatus of the present invention, as the heat insulation operation control unit, in the heat insulation operation under the control conditions after the first upper limit relaxation process is executed, a predetermined set time has elapsed since the start of the heat insulation operation. However, if the temperature in the detection path does not rise to the heat insulation operation stop temperature or more, the upper limit for further increasing the upper limit combustion amount after the first upper limit relaxation processing is performed within the range of the upper limit combustion amount or less during hot water supply operation While performing a relaxation process, it can be set as the structure which adds the increase process which increases the combustion amount in a heating part by predetermined amount (Claim 2). By doing so, even if the increase processing is not performed, even if the upper limit relaxation processing is executed once, for example, the heat radiation of the pipe is large, so most of the heat heated in the heat insulation operation is taken away, and after the circulation Even when the temperature returns to the heating section, the temperature rises to the heat insulation shutdown temperature without fail even if the temperature has dropped to almost the same as the original incoming water temperature. It is reliably avoided that it continues for an excessively long period of time.

  In the hot water supply apparatus of the present invention, an accumulation unit that integrates the energization time to the heat insulation operation control unit is provided, and as the heat insulation operation control unit, the energization time accumulated by the accumulation unit is set to represent a change in environmental factors. Each time when the predetermined set energization time is reached, the upper limit combustion amount after the upper limit relaxation processing is returned to the original initial value (Claim 3). By doing this, the environmental factor may have changed with the passage of the set energization time, so that the upper limit combustion amount that has been updated by learning is returned to the initial setting value, again under the current environmental factor, It is possible to determine the heat insulation operation stop temperature. Thereby, even if a seasonal variation, a change of installation environment, etc. arise, learning according to the environmental factor can be performed, and it becomes possible to perform the heat insulation operation by the heat insulation operation control part appropriately and effectively.

  Furthermore, in the hot water supply apparatus of the present invention, a release switch for releasing the restriction content related to the upper limit combustion amount acquired by the heat insulation operation control already executed by the heat insulation operation control unit can be provided. 4). By doing so, learning by the heat insulation operation control unit can be canceled and reset by the user's own intention, and the operation of the hot water supply apparatus in accordance with the user's intention can be realized.

  As described above, according to the hot water supply apparatus of the present invention, for example, at the turn of the season when the outside air temperature rapidly decreases, pipe heat dissipation increases, and most of the amount of heat applied by the combustion in the heating section. As a result of heat loss due to heat dissipation from the pipe, even if the circulation based on the heat insulation operation is continued, even if the temperature of the circulating hot water has hardly risen, Occurrence of a situation where continuous combustion continues for an excessively long time can be reduced. That is, if the detection path temperature does not rise to the heat insulation operation stop temperature even after the set time has elapsed, an upper limit relaxation process is performed to increase the initial upper limit combustion amount within the range of the upper limit combustion amount during the hot water supply operation. Therefore, if the amount of combustion determined according to the temperature of hot water returned by the circulation path including the return path exceeds the range of the upper limit combustion amount of the initial setting, the amount of combustion can be increased. Thus, the temperature rise up to the heat insulation operation stop temperature can be obtained early.

It is a schematic diagram which shows the example of the hot water supply apparatus which concerns on embodiment of this invention. It is a relationship diagram of the combustion number and supply gas pressure which took the case where it has the combustion stage of the 1st stage-the 6th stage as an example. It is a flowchart which shows the example of the heat retention driving | operation control of a hot water supply apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of a hot water supply device with an immediate hot water function according to the present invention.

  First, the overall configuration of the hot water supply apparatus 1 will be briefly described. Hot water to be heated is introduced into the heat exchanger 21 in the can 2 through the water supply path 3 and reaches a target temperature of a predetermined high temperature (for example, 75 ° C. at maximum) by the combustion heat of the combustion burner 22 in the heat exchanger 21. After the heat exchange heating, the hot water is discharged to the hot water supply path 4. Next, the temperature of the hot water that has been adjusted is adjusted to the set hot water temperature by mixing water from the bypass passage 6 in the mixing section 5 in the middle of the hot water, and the hot water after the temperature adjustment passes through the hot water supply passage 4 and the hot water supply pipe 7. Hot water is supplied up to 71. These water entry, hot water supply, and hot water supply are performed based on, for example, supply pressure from a water pipe connected to the upstream end of the water supply channel 3, pump supply water pressure from another supply system, or the like. In addition, in FIG. 1, although only one hot-water tap 71 is illustrated, it can be installed in a plurality of places such as a bathtub tap and a shower caran in addition to a hot-water tap in a kitchen or a washroom. It is configured.

  In addition, when the hot water supply is on standby (when the hot water supply is not used and is on standby until the hot water supply is used), the hot water in the hot water supply path 4 and the hot water supply pipe 7 is preliminarily kept at a predetermined temperature. A circulation circuit 8 is provided. That is, the immediate hot water circulation circuit 8 returns the hot water in the hot water supply path 4 and the hot water supply pipe 7 to the water supply path 3 by the operation of the circulation pump 81, thereby returning the water to the water inlet side of the can body 2 and heating it. 2 and the hot-water tap 71 side are circulated and heated to realize an instant hot water function. In the figure, reference numeral 30 denotes a check valve for preventing a reverse flow to the upstream side of the water supply passage 3, and reference numeral 80 denotes a check valve for preventing a reverse flow from the water supply passage 3 to the immediate hot water circulation circuit 8 side. Hereinafter, each component will be described in detail.

  The can 2 includes a combustion burner 22 that burns upon receiving supply of combustion air from the blower fan 9 and fuel gas from the fuel supply system 23, and a heat exchanger that is heat-exchanged and heated by the combustion heat of the combustion burner 22. 21 is built in. The combustion burner 22 and the heat exchanger 21 constitute a heating unit. The fuel supply system 23 includes a gas supply pipe 230, an original gas electromagnetic valve 231, and a gas proportional valve 232.

  The heat exchanger 21 includes a main heat exchanger 24 for heat exchange heating by sensible heat of the combustion gas, and a sub heat exchanger 25 for preheating by recovering latent heat of the combustion exhaust gas after passing through the main heat exchanger 24. The example comprised by is shown in figure. The inlet of the auxiliary heat exchanger 25 is connected to the downstream end of the water supply channel 3, and is preheated while passing through the auxiliary heat exchanger 25 and then subjected to heat exchange while passing through the main heat exchanger 24. The heated hot water is discharged to the upstream end of the hot water supply passage 4 connected to the outlet of the main heat exchanger 24.

  On the other hand, during the recovery of latent heat in the auxiliary heat exchanger 25, since the water vapor in the combustion exhaust gas is condensed, strongly acidic drain is generated. Therefore, the drain is collected by the drain pan 26, for example, a neutralization treatment tank ( The water is drained after being subjected to a neutralization treatment or the like (not shown). In addition, the point provided with the two types 24 and 25 as the heat exchanger 21 and the point provided with the component 26 for drain treatment are not essential in the present invention, and are heated by receiving water supply. If possible, the present invention can be applied. Therefore, the heat exchanger 21 can be configured only by the main heat exchanger 24 described above.

  The combustion burner 22 is configured to have a variable combustion quantity (variable combustion capacity), and thus, the tapping capacity is variable. As such a combustion burner 22, for example, a combustion burner 22 having a plurality of combustion nozzles that can be individually supplied with fuel by a gas on / off switching valve (capacity switching valve) is opened and closed by the controller 10. By performing the switching control, the number of combustion nozzles to be operated by combustion can be selectively changed and adjusted. The examples in the figure are grouped into two, one, two, four, eight, and four combustion nozzles from the right. If the capacity switching valve 221 is switched open, the two on the right end side in FIG. When the capacity switching valve 222 is opened and switched to the combustion pipe, the fuel gas is transferred to the one combustion pipe on the left side, and when the capacity switching valve 223 is opened and switched to the two combustion pipes on the left side. Supply is possible. Thereby, for example, the combustion capacity can be switched to six stages of 1 to 6 stages. In addition, the amount of combustion can be made variable by changing the flow rate of the gas supplied to the combustion nozzle of each stage. The continuous variable control of the combustion amount as described above enables the hot water discharge capacity, that is, the hot water discharge capacity in the range of a predetermined minimum output number (for example, No. 24) as a heat exchange heating amount in the main heat exchanger 24. It can be variable. Here, No. 1.0 is a hot water discharge capacity capable of raising the temperature of water at a flow rate of 1 L / min by 25 ° C., and corresponds to a product obtained by multiplying the heat generated by the amount of gas consumed by combustion by the heat exchange efficiency. To do. Combustion control for heating the supplied hot water to a target temperature using the combustion burner 22 with variable combustion amount will be described later.

  In the water supply path 3, the upstream end of the bypass path 6 is branched from a branch position 31 in the middle of the water supply path 3, and the return path 83 of the immediate hot water circulation circuit 8 at the junction position 32 downstream (can body 2 side) from the branch position 31. The downstream ends of the two are joined together. The check valve 30 is interposed in the water supply path 3 upstream of the junction position 32 and downstream of the branch position 31. Further, in the water supply passage 3 downstream of the joining position 32, an incoming water flow sensor 33 for detecting an incoming water flow rate of water entering the can body 2, and an incoming water temperature sensor 34 for detecting the incoming water temperature, Are intervened. In addition, the code | symbol 35 in FIG. 1 is a drain plug, and the drain valve 35 is provided with the safety valve 36 for preventing overpressure. The safety valve 36 opens when an abnormal water pressure acts in the flow path and exceeds a predetermined upper limit internal pressure (for example, 2 kPa), and releases the excess pressure to the outside.

  In the hot water supply path 4, a can body temperature for detecting a tapping temperature (can body temperature) of high-temperature hot water heated by heat exchange heat from the can body 2 between the outlet of the heat exchanger 21 and the mixing unit 5. A sensor 41 and a hot water flow rate adjustment valve 42 are interposed. Further, a hot water supply path 4 at a position downstream of the mixing unit 5 is provided with a hot water temperature sensor 43 for detecting the temperature of the hot water after the temperature is adjusted by the mixing unit 5. The upstream end of the hot water supply pipe 7 is connected to the connection port 44 at the downstream end of the hot water supply path 4, and the hot water supply tap 71 is connected to the downstream end of the hot water supply pipe 7. In addition, the hot water tap 71 can be directly connected to the connection port 44 of the hot water supply path 4, and in this case, the installation of the hot water supply pipe 7 is omitted. The hot water supply path 4 and the hot water supply pipe 7 constitute a “hot water supply path” for discharging hot water from the heat exchanger 21 and supplying hot water toward the downstream end via the mixing unit 5.

  In addition to the hot water supply path 4, the mixing section 5 is connected so that the downstream end of the bypass path 6 joins. Through this bypass channel 6, water diverted from the water supply channel 3 can be introduced into the mixing unit 5. The mixing unit 5 constitutes a joining part of the hot water supply path 4 and the bypass path 6. A bypass flow rate sensor 61 that detects a bypass flow rate that is diverted from the water supply passage 3 and a bypass flow rate adjustment valve 62 are interposed in the bypass route 6. Then, a predetermined amount of water from the bypass passage 6 is mixed (mixed water) with the hot water from the hot water supply passage 4 in the mixing section 5 by the opening degree control for the bypass flow rate adjustment valve 62 by the controller 10 described later. The hot water adjusted to a predetermined set hot water supply temperature (for example, 43 ° C.) can be supplied toward the connection port 44 of the hot water supply passage 4.

  The immediate hot water circulation circuit 8 includes a return path 83 whose downstream end is connected from the connection port 82 at the upstream end to the joining position 32 of the water supply path 3, and a branch position 84 set in the hot water supply pipe 7 near the hot water tap 71. A return flow path 86 comprising a return pipe 85 branched at the upstream end and connected at the downstream end to the connection port 82 is provided. The circulation pump 81 is interposed in the return path 83, and the check valve 80 is built in the connection port 82. When the circulation pump 81 is operated by the heat insulation operation control, the hot water remaining in the hot water supply pipe 7 and the like is returned to the water supply path 3 at the junction position 32 through the return pipe 85 and the return path 83. . The hot water returned to the water supply path 3 is then sent to the heat exchanger 21 and heated by the combustion heat of the combustion burner 22 and then returned to the hot water tap 71 side through the hot water supply path 4 and the hot water supply pipe 7. Will be circulated. Thus, the return pipe 85, the return path 83, the water supply path 3 downstream from the joining position 32, the flow path in the heat exchanger 21, and the hot water supply path are paths through which hot water is circulated by the operation of the circulation pump 81. 4 and the hot water supply pipe 7 constitute a circulation path of the immediate hot water circulation circuit 8, and the circulation path is constituted by a path built in the hot water supply apparatus except for the return pipe 85 and the hot water supply pipe 7 installed in the field. 11 is configured.

  The operation control of the hot water supply apparatus is executed by the controller 10. That is, operation control such as hot water supply operation control for supplying hot water at the set hot water supply temperature set in the remote controller 101 and heat insulation operation control executed during standby for hot water supply, for example, set hot water supply temperature from the remote controller 101 installed in the kitchen, etc. The controller 10 receives the output of the setting signal, the operation signal, etc., and the output of the detection signal from various temperature sensors. The controller 10 constitutes a control unit, and includes a microcomputer having an MPU and a rewritable memory, and performs the hot water supply operation control and the like based on programs and various data stored in the memory. .

  The remote controller 101 is provided with an instant hot water switch 102 that allows a user to switch whether to allow or reject the execution of the thermal insulation operation control. The function of the release switch for releasing is added. If the user turns on the hot water switch 102 in advance, it is possible to execute the heat insulation operation control as described later, and if it is turned off, the heat insulation operation control can be prevented from being performed during the hot water supply standby. Also, if the user switches off the hot water switch 102 that has already been turned on, the heat insulation operation control is canceled at that point regardless of whether the heat insulation operation control is executed or not, and the heat insulation operation until that time is stopped. The learning content described below regarding the temperature is canceled and returned to the initial set value, and the integrated value of the energization time is cleared. Thereby, learning by heat insulation operation control, etc. can be canceled and reset by the user's own intention, and the operation of the hot water supply apparatus in accordance with the user's intention can be realized.

  In the hot water supply operation control, the hot water tap 71 is opened by the user, and accordingly, water enters the water supply path 3 and the incoming water flow rate sensor 33 detects that the incoming water flow rate has exceeded a predetermined minimum operating flow rate. Then, control is started and combustion of the combustion burner 22 is started. The required amount of combustion (combustion number) in the combustion burner 22 is the incoming water temperature detected by the incoming water temperature sensor 34, the incoming water flow rate detected by the incoming water flow rate sensor 33, and the target temperature for heating by the heat exchanger 21. (For example, 65 ° C.), and combustion control is performed so that a predetermined combustion amount is obtained based on the calculation result. Thereby, predetermined high temperature hot water is supplied to the mixing unit 5 through the hot water supply path 4. Then, as temperature control by mixed water in the mixing unit 5, the incoming water temperature detected by the incoming water temperature sensor 34, the can body temperature detected by the can body temperature sensor 41, the incoming water flow rate sensor 33 and the bypass flow rate sensor 61. On the basis of the detected flow rate, the mixed water flow rate from the bypass passage 6 is calculated so that the hot water after mixing reaches the set hot water supply temperature, and the opening degree control of the bypass flow rate adjustment valve 62 is controlled based on the calculation result. Done. As described above, hot water having the set hot water temperature is supplied to the hot water tap 71, and the hot water is discharged from the hot water tap 71.

The details of the combustion control example will be described below. Usually, first, based on the detected values from the incoming water flow rate sensor 33 and the incoming water temperature sensor 34, based on the FF (feed forward) control number corresponding to the target temperature. Next, the combustion operation is performed, and then the combustion operation is performed in consideration of the FB (feedback) control number based on the detection value from the can body temperature sensor 41. The FF control number g1 is the amount of combustion required to raise the incoming water to the target temperature based on the incoming water flow rate Qi from the incoming water flow rate sensor 33, the incoming water temperature Ti from the incoming water temperature sensor 34, and the target temperature. It is obtained by the calculation of the following formula as (combustion number)
g1 = {(Ts−Ti) × Qi} / 25 ° C.
Based on the obtained combustion number g1, the combustion stage (for example, 4th stage: see FIG. 2) and the supply gas pressure that can output this combustion number are determined, and the combustion nozzle corresponding to the 4th stage is corresponded. The combustion gas is supplied at the supply gas pressure. As a result, proportional combustion is performed with the required amount of combustion obtained by calculation, and the incoming water is heat-exchanged and heated to a predetermined target temperature.

  When the hot-water tap 71 is closed by the user, the flow of water in the water supply channel 3 stops, and the detected value of the incoming water flow rate sensor 33 becomes smaller than the minimum operating flow rate. Operation control ends. Then, the hot water supply 71 is in a hot water supply standby state until the time when the hot water supply 71 is opened again by the user.

  Next, the heat insulation operation control will be described with reference to FIG. In the following heat insulation operation control, when the hot-water tap 71 is opened during use of the heat insulation operation and the use of the hot water supply is started, the heat insulation operation is immediately stopped and the hot water supply operation control is performed. . As a premise of the heat insulation operation control, when the outlet 103 (see FIG. 1) is inserted into the power source and energization of the MPU of the controller 10 is started, integration of the energization time is started (step S1). And after hot water supply use is started by ON operation of the operation switch and opening operation of the hot-water tap 71, when the hot water supply operation control is finished, monitoring by the heat insulation operation control is started. First, it is determined whether or not the integrated energization time is less than or equal to the set energization time. After confirming that the accumulated energization time is less than or equal to the set energization time (YES in step S2), then the detected path temperature is equal to or lower than the heat insulation operation start temperature. It is determined whether or not it has decreased (step S3). If the temperature in the detection path is lowered to the heat retention operation start temperature or lower, the heat retention operation is started, and the accumulation of the combustion time related to the heat retention operation is also started (YES in step S3, S4, S5).

  Here, the in-path temperature is the temperature of the hot water in the circulation path 11, and as the in-path temperature, for example, a tapping temperature detected by a tapping temperature sensor 43 can be used. The heat insulation operation start temperature and the heat insulation operation stop temperature described later are temperature values that are preset in advance for the heat insulation operation control, and can be determined in principle in relation to the set hot water supply temperature. The purpose of the heat insulation operation is to allow hot water of a desired temperature (set hot water temperature) to be immediately discharged from the hot water tap 71 when the hot water is used next time, so that it can be determined in relation to the set hot water temperature. Because it is reasonable. For example, in the case of using the tapping temperature as the in-road temperature, [set hot water supply temperature−Ts] ° C. can be set as the heat insulation operation start temperature, and [set hot water supply temperature + Te] ° C. can be set as the heat insulation operation stop temperature. For example, about 5 ° C. can be used as the temperature value Ts, and about 2 to 5 ° C. can be used as Te. In particular, the heat insulation operation stop temperature can change the value of Te according to the temperature value of the set hot water supply temperature. In this case, the higher the set hot water supply temperature, the larger the value of Te. For example, if the set hot water supply temperature is 43 ° C., Te = 2 ° C., and if it is 45 ° C., Te = 5 ° C. can be set.

  The temperature detected by the tapping temperature sensor 43 can be used as the temperature in the road to be monitored for the heat insulation operation stop temperature, or by a temperature sensor disposed at another position of the circulation path 11. The detected temperature can also be used. For example, using the temperature of hot water flowing through the circulation path 11 of the part returned from the hot water tap 71 that is the hot water supply destination, specifically, for example, the temperature of the hot water detected by the water temperature sensor 34 as the temperature in the road, the heat insulation operation is performed. It can be compared with the stop temperature. In addition, when a switch (for example, a Dip switch) for allowing or prohibiting high temperature hot water (for example, high temperature hot water of 60 ° C. or higher) is provided, the heat insulation operation set in advance in relation to the set hot water temperature is started. Instead of the temperature, the heat insulation operation start temperature can be initialized by another way of thinking.

  In the heat insulation operation in step S4, first, the circulation pump 81 is operated, and then the combustion burner 22 is operated for combustion. At this time, as the combustion control for the heat retaining operation, the upper limit number of stages of combustion is limited to the minimum side in advance, and continuous combustion is performed within the minimum combustion amount range. That is, one stage is initially set as the upper limit of the number of combustion stages. In the example of FIG. 1, only the capacity switching valve 221 is opened and the two combustion nozzles are operated to burn, whereby the combustion number range of G1 ( The proportional combustion in FIG. 2) is performed as a heat retention operation. At the first time of the heat insulation operation, in order to increase the temperature quickly, the restriction on the upper limit of the number of combustion stages is removed only for a short predetermined time (for example, 5 minutes) immediately after the start of the heat insulation operation, and the original maximum combustion is performed. Proportional combustion can be performed within a combustion number range up to the number of stages (six stages in the figure). In this case, after the predetermined time elapses, the combustion shifts to proportional combustion within the upper limit (within the G1 range) of the number of combustion stages limited by the initial setting.

  Then, after confirming that the accumulated combustion time, that is, the duration of the heat insulation operation is equal to or less than the set combustion time (YES in step S6), it is determined whether or not the temperature in the detection path has risen to the heat insulation operation stop temperature or more. (Step S7). If the temperature has not risen to the heat insulation operation stop temperature, the process returns to step S6 to repeat the determination on the accumulated combustion time, and then repeat the determination on the heat insulation operation stop temperature in step S7. If the temperature in the detection path rises above the temperature retention stop temperature (YES in step S7), the temperature retention operation is stopped (step S8). That is, the combustion operation of the combustion burner 22 is stopped, and the circulation pump 81 is stopped. Then, the integrated value of the combustion time is cleared and the process returns to step S1 (step S9).

  On the other hand, in the determination of step S6, when the accumulated combustion time is not less than the set combustion time (for example, 1 hour), that is, when the combustion for the heat insulation operation continues beyond the set combustion time (NO in step S6). Then, the upper limit relaxation process for relaxing the restriction on the upper limit of the number of combustion stages, that is, the upper limit of the number of combustion stages is changed to one stage (that is, two stages) (step S10). Then, after clearing the integrated value of the combustion time (step S11), the process returns to step S5 to start the integration of the combustion time from the beginning and start the heat insulation operation under the new combustion conditions (step S5). While the combustion time has elapsed, it is monitored whether or not the temperature has been raised to the heat insulation operation stop temperature (YES in step S6, NO in step S7). If the temperature in the road rises to the heat insulation operation stop temperature (YES in step S7), the heat insulation operation is stopped (step S8), and the process returns after clearing the integrated value of the combustion time (step S9).

  As a result of the upper limit relaxation processing of the number of combustion stages to two in the above step S10, the combustion by the combustion burner 22 can be operated by three combustion nozzles by opening both the capacity switching valves 221 and 222. , G2 (see FIG. 2), proportional combustion within the range of the number of combustion is possible. For this reason, when the required combustion number calculated according to the temperature of the hot water returned by the return path 83 exceeds the combustion number range G1 in one stage, the combustion amount can be increased. A temperature increase up to the heat insulation operation stop temperature can be obtained at an early stage.

  However, even if the second heat insulation operation is performed after the first upper limit relaxation process, it may be possible that the temperature does not rise to the heat insulation operation stop temperature during the set combustion time (NO in step S7). NO in step S6). For example, although the hot water temperature rises by the second heat insulation operation and approaches the heat insulation operation stop temperature, since the heat radiation from the pipe is large, most of the heated heat is deprived and returned to the heat exchanger 21 after circulation. In some cases, the temperature has dropped to about the same as the original incoming water temperature. In such a case, the upper limit of the number of combustion stages is further changed to one stage (that is, three stages), and a predetermined combustion amount (combustion number) α is compulsory for the combustion amount calculation result in the subsequent proportional combustion. An increase process of increasing the number is added (step S10). That is, after adding the above α amount to the combustion number calculated to heat a predetermined amount in the heat exchanger 21 based on the incoming water temperature, incoming water flow rate, etc. (for example, see g2 in FIG. 2) It burns with the combustion number (g2 + α). By performing the heat insulation operation by the combustion operation in which the increase treatment is added in addition to the upper limit relaxation treatment, the temperature rise to the heat insulation operation stop temperature can be surely obtained, and thus the combustion operation is excessively prolonged. It will be suppressed from continuing.

  In this manner, the process (step S10) such as the restriction on the upper limit number of combustion stages (the restriction on the upper limit combustion amount) is gradually relaxed is repeated, and the initially set restriction is the environment such as the season at that time. It is updated by learning according to changes in piping heat radiation based on the factors.

  As a result, for example, pipe heat dissipation increases at the turn of the season when the outside air temperature drops sharply, or movement of external pipes (hot water supply pipe 7 and return pipe 85) occurs due to relocation of the hot water supply device. Even in an environment where there is a change in environmental factors such as a change in the environment or a change in the installation environment, the combustion burner 22 continues to burn for an excessively long time as the heat insulation operation is performed. You will be able to avoid the situation. In addition, since it is considered that the temperature in the road is quickly lowered to the heat insulation operation start temperature after the heat insulation operation is stopped, the next heat insulation operation is started early, so that the heat insulation function (instant water function) in the environment is also ensured. Will be able to.

  By performing the update by learning the heat insulation operation start temperature as described above, the above-described effects in the environment at that time can be obtained, but the seasons change sequentially. Alternatively, there may be a case where an installation environment such as a construction for changing the installation location of the external pipe changes during the period. For this reason, when the cumulative energization time exceeds the set energization time in the determination of step S2 (NO in step S2), the setting contents regarding the limit relating to the upper limit combustion stage number that has been updated by learning are initialized to the upper limit combustion stage number. After the content related to the restriction is returned to the initial setting value (the upper limit step number is 1) (step S12), the integrated value of the integrated energization time is cleared (step S13), and the process returns. In other words, the passage of time is monitored, and environmental factors (seasonal factors and installation environment) may have changed over the course of a predetermined period. The determination is made again regarding the upper limit combustion stage number and the execution of the increase process under the current environmental factors. As a result, even if seasonal fluctuations or changes in the installation environment occur, learning can be performed according to the environmental factors, and the heat insulation operation control can be executed appropriately and effectively. As the set energization time, for example, a time value corresponding to one month to three months can be set, and a shorter time value (for example, a time value corresponding to one month) to reflect changes in environmental factors finely, In order to realize the minimum reflection, a longer time value (for example, a time value corresponding to 3 months) can be set as the set energization time.

<Other embodiments>
The present invention is not limited to the above-described embodiment, but includes various forms. That is, as the set combustion time (predetermined set time), if the in-road temperature does not rise to the heat insulation operation stop temperature within the set combustion time in the first heat retention operation, the setting in the second and subsequent heat insulation operations is performed. The combustion time can be set to a different time value from that of the first time. Furthermore, the set combustion time in the third heat retention operation can be set to a time value different from that in the second time.

  The following configuration can be adopted as an applied technique of the present invention. That is, if the temperature in the detection path does not rise to the heat insulation operation stop temperature or more even after a predetermined set time has elapsed after the heat insulation operation is started, first, the initial value of the heat insulation operation stop temperature is set. Replace with the detected temperature in the road, that is, the temperature in the detected road at that time is newly set and updated as the heat insulation operation stop temperature, and the heat insulation operation is performed using the newly set heat insulation operation stop temperature. It is determined whether or not to stop. Even in such a case, in the subsequent heat insulation operation, if the temperature in the detection path does not rise to the heat insulation operation stop temperature or higher even after a predetermined set time has elapsed since the heat insulation operation was started, In addition, the upper limit relaxation process, the upper limit relaxation process, and the increase process in the embodiment can be executed.

  In the embodiment, the energization time is accumulated by the counter timer (accumulation unit) in the controller 10, and learning / update related to the upper limit combustion stage number (limit on the upper limit combustion amount) is performed as the set energization time elapses. Initialization is made to respond to changes in environmental factors (season), but instead, for example, the detection value of an ambient temperature sensor (outside temperature sensor) is used, or the calendar function (date data) by the controller 10 is used. The learning / updating can be initialized by using.

  In the above embodiment, the upper limit number of combustion stages is used as the upper limit combustion quantity. However, the present invention is not limited to this, and the combustion quantity in the middle of proportional control at a specific number of combustion stages can be used. Further, if the combustion burner is not divided into a plurality of combustion stages and is configured such that the combustion amount is adjusted only by adjusting the gas supply pressure (gas supply flow rate), the upper limit fuel amount is the upper limit fuel amount. Supply pressure or an upper limit fuel supply can be used.

3 water supply channels (circulation channels)
4 Hot water supply path (circulation path)
10 Controller (Insulation operation controller)
21 Heat exchanger (heating unit)
22 Combustion burner (heating unit)
34 Water supply temperature sensor (temperature sensor)
43 Hot water temperature sensor (temperature sensor)
71 Hot water tap (hot water supply destination)
81 Circulation pump 83 Return path (circulation path)
102 Instant hot water switch (release switch)

Claims (4)

A water supply channel, a heating unit for heat exchange heating the water supplied through the water supply channel with combustion heat, and a hot water supply channel for supplying hot water heat-exchanged and heated in the heating unit toward the hot water supply destination A circulation path including a return path for branching from the vicinity of the hot water supply destination and returning the hot water to the water supply path, a circulation pump, and heating the heating pump by operating the circulation pump during standby of hot water supply A hot water supply device including a heat insulation operation control unit for performing a heat insulation operation for circulating the hot water between the hot water supply destination and keeping the inside of the circulation path,
A temperature sensor for detecting the temperature of the hot and cold water in the circulation path;
The heat insulation operation control unit
The circulating hot water is heated by burning the heating unit within the range of the default upper limit combustion amount that is limited to be lower than the upper limit combustion amount during hot water supply operation, and the temperature in the detection path detected by the temperature sensor When the temperature becomes equal to or lower than a preset temperature keeping operation start temperature, the temperature keeping operation is started. On the other hand, when the temperature in the detection path rises above a preset temperature keeping operation stop temperature by the heat keeping operation, the temperature keeping operation is stopped. And configured as
If the temperature in the detection path does not rise above the heat insulation operation stop temperature even after a predetermined set time has elapsed since the heat insulation operation was started, the initial upper limit combustion amount is set to the upper limit combustion during the hot water supply operation. It is configured to update the limit content related to the upper limit combustion amount by performing an upper limit relaxation process that increases in the range below the amount,
A water heater characterized by that. The hot water supply device according to claim 1,
In the heat insulation operation under the control condition after the first upper limit relaxation process is executed, the heat insulation operation control unit is in the detection path even if a predetermined set time has elapsed since the heat insulation operation was started. If the temperature does not rise above the heat retaining operation stop temperature, an upper limit relaxation process for further increasing the upper limit combustion amount after the first upper limit relaxation process is performed within a range equal to or lower than the upper limit combustion amount during the hot water supply operation. A hot water supply apparatus configured to add and increase processing to increase a combustion amount in the heating unit by a predetermined amount. The hot water supply device according to claim 1 or 2,
An integration unit for integrating the energization time to the heat insulation operation control unit,
The warming operation control unit is configured to reduce the upper limit combustion amount after the upper limit relaxation process every time the energization time accumulated by the accumulation unit reaches a predetermined set energization time set to represent a change in environmental factors. A water heater configured to return the original value to the original value. The hot water supply device according to any one of claims 1 to 3,
A hot water supply apparatus, comprising: a release switch for releasing a restriction content relating to an upper limit combustion amount acquired by the heat insulation operation control already executed by the heat insulation operation control unit.

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